Dyeing cellulose ester and ether



Patented Aug. 12, 1930 UNITED STATES PATENT OFFICE LEsLIE GORDON LAWRIE, EEANK WILLIAM LINCH, AND EENEsnnAEEY RODD, OF

BLACKLEY, MANCHESTER, ENGLAND, AssIGNoEs 'ro BRITISH DYESTUFFS CORPO- RATION LIMITED, OF MANoEEsrEE, ENGLAND DYEING CELLULOSE ESTER AND ETHER No Drawing. Application filed June 21, 1928, Serial No. 282,346, and in Great Britain July 5, 1927.

,It is well known that malachite green and brilliant green (Colour Index Nos. 657 and 662) give green shades on acetatesilk and other cellulose ester or ether materials, but their practical application has been restricted because the dyeings fade during storage, particularly when exposed to alkaline conditions. v

Our invention relates to a method whereby beautiful green dyeings may be obtained on acetate silkand similar materials, the shades being little afiected even in a strongly-alkaline atmosphere.

We have discovered that this desirable effect may be achieved by using certain compounds of the malachite green and brilliant green type having, in the anhydride salt form, for example the hydrochlorides, the general formula store the green shade of the dye. The presence of the alkyl group in the position 2 changes the colour from green to blue, but

' we have-found that the green shade is restored by suitably substituting also posi-. tions 4 or 5 or both, e.- g. by alkyl or alkoxy A dye of the above structure in which R=R'R"=methyl, and in which X is a nitrogroup and Y is hydrogen, gives blue shades, but dyes ofthis general structure can be obtained which give green shades. In particular we may mention the 2: 4-dimethyl compound, obtained e. g., by condensing pp'-tetramethyl diamino benzhydrol with m-xylene and oxidizing the product, or by con-v densing 2: 4-dimethylbenzaldehyde with two l-chloro-m-xylene in the presence of sodium by the process described in our application Serial No. 251,458 dated 2nd February, 1928. Another such dye isthe 2: 5-dimethyl derivative of malachite green, prepared e.- g. by condensing Cpp-tetramethyl-diaminobenzophenone with 2-chloro-p-xylene in the presence of sodium.

Our invention is illustrated, but not limited, by the following example, in which the parts are by weight.

A dyebath is made containing 1% (calculated on the weight of material to be dyed) of the 2:4-dimethyl derivative of malachite green (as oxalate or other salt) and of common salt. 1

The cellulose acetate silk, after washing or scouring is entered into the cold dyebath andthe temperature raised slowly to 75-80 (1.,

the bath being kept at this temperature for minutes.

After dyeing the material is soaped in a 0.25% solution of neutral soap for 10-15 minutes at 40 C and washed in warm water. The dyedsilk is then acidified in a bath containing about oz. of 30% acetic acid in 10 gallons of water and dried without rms- %&,bright green shade, fast to light, to alka lies. and 'to alkaline storage is produced.

.Using oxalate of 2:4-dimethyl brilliant green, obtained by condensing tetraethyld1- aminobenzophenone with 4-chloro-m-xylene by meansof sodium a slightly greener and brighter shade-with similar properties is obtained. I

What we claim and desire to secure by Letters Patent is p l 1. A process for dyeing cellulose esters and 21 P iiw in which R and R" are either methyl or ethyl groups, R is an alkyl grou Z is a salt forming radical, and of X and .one is an alkyl or alkoxy group. I In testimony whereof we aflix our signaethers in green shades characterized by the 1 application to the material of an anhydride salt of an unsulphonated triarylmethane derivative, the said anhydride salt having the formula where methyl and ethyl groups are both represented by R',.R is an alkyl )group, Z is as'alt forming radical, and of and Y at least one is an alkyl or alkoxy group and the other is hydrogen or any substituent except the sulpho group.

2. A process for dyeing cellulose esters and ethers in green shades characterized by the application to the material of an anhydride salt of an unsulphonated triarylmethane derivative, the said anhydride salt having the iormula g: Q CH.

where methyl and ethyl groups are both represented by R, and Z is a salt forming radical.

3. Material made of cellulose esters or ethers and dyed in a green shade with an an- I hydride salt of an unsulphonated triarylmethane derivative, the said anhydride salt having the formula tures. v

LESLIE GORDONLAWRIE. FRANK WILLIAM LINCH. ERNEST HARRY RODD.

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